Schedule 17 


April 8,1921 


DEPARTMENT OF THE INTERIOR 

ALBERT B. FALL, Secretary 

l/ S, BUREAU OF MINES 

m 

H. FOSTER BAIN, Director 


PROCEDURE FOR TESTING EXPLOSIVES FOR 
PERMISSIBILITY FOR USE IN GASEOUS 
AND DUSTY COAL MINES 

WITH 

TEST REQUIREMENTS, TOLERANCE 
LIMITS, AND THE SCHEDULE OF FEES 



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WASHINGTON 

GOVERNMENT PRINTING OFFICE 
1921 


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The Bureau of Mines, in carrying out one of the provisions of its organic 
act—to disseminate information concerning investigations made—prints a 
limited free edition of each of its publications. 

When this edition is exhausted, copies may be obtained at cost price only 
through the Superintendent of Documents, Government Printing Office, Wash¬ 
ington, D. C. 

The Superintendent of Documents is not an official of the Bureau of Mines. 
His is an entirely separate office and he should be addressed: 

Superintendent of documents, 

Government Printing Office, 

Washington, D. C. 

The general law under which publications are distributed prohibits the giving 
of more than one copy of a publication to one person. The price of this pub¬ 
lication is 5 cents. 


2 


First edition, July, 1921. 



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PROCEDURE FOR TESTING EXPLOSIVES FOR PERMISSIBILITY, WITH TEST 
REQUIREMENTS, TOLERANCE LIMITS, AND SCHEDULE OF FEES. 


AUTHORIZATION. 

An Act of Congress (37 Stat., 681) approved February 25, 1913, 
contains the following provision in regard to tests or investigations 
performed by the Bureau of Mines: 

That for tests or investigations authorized by the Secretary of the Interior, 
under the provisions of this act, other than those performed for the Govern¬ 
ment of the United States, or State governments within the United States, a 
reasonable fee covering the necessary expenses shall be charged, according to 
a schedule prepared by the Director of the Bureau of Mines and approved by 
the Secretary of the Interior, who shall prescribe rules and regulations under 
which such tests or investigations may be made. All moneys received from 
such sources shall be paid into the Treasury to the credit of miscellaneous 
receipts. 

The following schedule of fees to be charged on and after April 8, 
1921, has been established and approved by the Secretary of the In¬ 
terior in accordance with the provisions of the statute just quoted. 
The conditions under which these explosives are tested are given 
below. 

DEFINITION OF A PERMISSIBLE EXPLOSIVE. 

A permissible explosive is an explosive which is similar in all re¬ 
spects to the sample which has passed certain tests prescribed by the 
Bureau of Mines to determine its safety for use in gaseous and dusty 
coal mines, and when used in accordance with the conditions pre¬ 
scribed by the bureau. 

While permissible explosives are designed especially for use in 
gaseous and dusty coal mines, they are suitable for use in other coal 
mines and for many other blasting operations. 

PRESCRIBED CONDITIONS FOR USE OF PERMISSIBLE EXPLOSIVES. 

I. That the explosive is in all respects similar to the sample sub¬ 
mitted by the manufacturer for test. 

II. That detonators—preferably electric detonators—are used of 
not less efficiency than those prescribed, namely, those consisting by 
weight of 90 parts of mercury fulminate and 10 parts of potassium 
chlorate (or their equivalents). 

III. That the explosive, if frozen, shall be thoroughly thawed in a 
safe and suitable manner before use. 

(3) 


55248°—21 



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IV. That the quantity used for a shot does not exceed 1-J pounds 
(680 grams) and that it is properly tamped with clay or other non¬ 
combustible stemming. 

CONDITIONS UNDER WHICH AN OTHERWISE PERMISSIBLE EX¬ 
PLOSIVE IS NOT PERMISSIBLE. 

After an explosive has passed the required tests and its brand name 
has been published in a list of permissible explosives, it is not a per¬ 
missible explosive if one or more of any of the following conditions 
prevail: 

1. If kept in an improper place until it undergoes a change in 
character. 

2. If used in a frozen or partly frozen condition. 

8. If used in excess of 1-J pounds (680 grams) per shot. 

4. If the diameter of the cartridge is less than that designated in 
the column “ smallest permissible diameter.’' 

5. If fired with a detonator or electric detonator of less efficiency 
than that prescribed. 

6. If fired without stemming. 

7. If fired with combustible stemming. 

8. If fired in the presence of a dangerous percentage of fire damp. 

EXPLOSIVES NOT TO BE CONSIDERED PERMANENTLY PER¬ 
MISSIBLE. 

Moreover, even when all of the prescribed conditions have been 
met, no explosive on the permissible list should necessarily be con¬ 
sidered as being permanently a permissible explosive, for the bureau 
reserves the right, on fuller information concerning the conditions 
that lead to safety, to revise this list; but any permissible explosive 
when used under the prescribed conditions may properly continue 
to be considered a permissible explosive until notice of its withdrawal 
or its removal from the list has been officially published, or until its 
name is omitted from a later list published by the Bureau of Mines. 

Furthermore, the manufacturers of a permissible explosive may 
withdraw it at any time. Manufacturers are urged to do so when 
replacing a permissible explosive by one of superior qualities. 

Permissible explosives will be placed on an inactive list at the 
request of the manufacturer, or if they have not been manufactured 
during any calendar year. The distinction between the inactive list 
and the active list of permissible explosives is that the inactive list 
is not published. The bureau will transfer explosives from the 
inactive list to the active list of permissible explosives upon the 
request of the manufacturer, in accordance with the regulations then 
in force, and without cost to him. 

After further experiments and conferences the Bureau of Mines 
may find it advisable to adopt additional and more severe tests to 


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which all permissible explosives may be subjected, in the hope that 
through the use of such explosives only as pass the more severe tests 
the lives of miners may be better safeguarded. 

COMPLETE OFFICIAL TEST. 

A complete official test of an explosive to determine its permis¬ 
sibility for use in coal mines shall consist of physical examination, 
small lead-block test, rate of detonation, flame test, gallery tests 1 
and 4, ballistic pendulum, explosion by influence, gaseous products 
of combustion, pendulum friction, freezing test by crusher board (for 
explosives marked low-freezing), chemical analysis, and if the manu¬ 
facturer so desires, the pressure by Bichel-gage test. 

In addition, the bureau will carry out, at the request of the manu¬ 
facturer or applicant, the Trauzl lead-block test, calorimeter test, 
small-impact test, large-impact test, and maximum-pressure test by 
Bichel pressure gauge, for which additional fees will be charged in 
accordance with this schedule. 

TEST REQUIREMENTS OF EXPLOSIVES FOR ADMITTANCE TO PER¬ 
MISSIBLE LIST. 

All explosives submitted for admittance to the permissible list 
of explosives must pass the following chemical and physical tests 
without showing any unfavorable results. 

An explosive will be considered unsatisfactory if it is not chemi¬ 
cally stable, if it shows leakage of liquid explosive ingredient, or if 
it is in such condition that exudation of liquid explosive ingredient 
would occur in handling or transportation. 

POISONOUS GASES. 

A 680-gram (lj-pound) charge of explosive and original wrapper 
must not evolve 158 liters (5J cubic feet) or more of poisonous gases. 
The poisonous gas that is likely to be evolved on detonation of a per¬ 
missible explosive is carbon monoxide. Under special conditions 
hydrogen sulphide and oxides of nitrogen may be evolved. 

GRADE OF ELECTRIC DETONATOR. 

Each charge shall be fired with the grade of electric detonator 
recommended by the manufacturer for use with the explosive, but 
the detonator can not be less than a No. 6; an electric igniter may be 
used with a slow-burning explosive. 

COMPLETE DETONATION. 

The failure of two or more charges to detonate or explode com¬ 
pletely in the course of the official tests will be considered an unfavor¬ 
able result when the charges are fired with a suitable detonator 
under a confinement equal to or greater than one atmosphere. 

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UNIT DEFLECTIVE CHARGE. 

The unit deflective charge is that weight of an explosive in 
grams which gives the same swing on the ballistic pendulum as 
'227 grams (J pound) of Pittsburgh testing station standard 40 
per cent straight nitroglycerin dynamite. 

The bureau requires that this unit deflective charge of said ex¬ 
plosive shall not exceed 454 grams (1 pound), as tests have shown 
that explosives whose unit deflective charge exceeds 454 grams (1 
pound) will require on account of the lack of strength more than 680 
grams (1J pounds) in a single charge to blast down coal satisfactorily, 
and when so used are not permissible in accordance with requirement 
No. IV in the prescribed conditions of use, page 4. 

PENDULUM FRICTION TEST. 

An explosive must pass a pendulum friction test on the Bureau 
of Mines pendulum friction device—10 trials on the steel anvil with 
the fiber-faced steel shoe falling from a height of 1\ meters (59.1 
inches) and carrying an added weight of 20 kilograms (44 pounds) 
—without showing any more unfavorable result than an almost in¬ 
distinguishable crackling. A charge of 7 grams of explosive is 
used in each trial. 

• GALLERY TESTS. 

An explosive before admittance to the Bureau of Mines permis¬ 
sible list must pass without a single ignition the following tests in 
the gas and dust gallery No. 1 of the Bureau of Mines: 

Test No. 1 .—Ten trials with a charge equal to the unit deflective 
charge, each charge being tamped with 1 pound of dry fire-clay 
stemming fired into a mixture of natural gas and air containing 
8 per cent methane and ethane at a temperature of 77° F. 

Test No. 1 ±.—Five trials with a lj-pound charge of the explosive 
fired without stemming into a mixture of natural gas and air con¬ 
taining 4 per cent of methane and ethane and 20 pounds of bitu¬ 
minous coal dust, 18 pounds of which is to be placed on shelves 
along the sides of the first 20 feet of the gallery and 2 pounds to 
be so placed that it will be stirred up by an air current in such a 
manner that all or part of it will be suspended in the first division 
of the gallery, at a temperature of 77° F. 

FEES. 

1. For a complete official test of each explosive to determine its per¬ 


missibility for use in coal mines_$150. 00 

2. In case of the failure of an explosive to pass a complete official test- 75. 00 

3. Physical examination (for each size of cartridge)_ 1.00 

4. For three experimental small lead-block tests_ 3 . oo 

5. For three rate of detonation tests_ 7 . oo 

6. For three experimental shots in flame-test apparatus_ 3. 00 







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7. For each experimental shot in gallery: 

Test No. 1_ $2.00 

Test No. 4_ IB. 00 

8. For three experimental shots in ballistic pendulum_ 17. 00 

9. Explosion by influence_ 6. 00 

10. For one gauge test to determine the gaseous products of combustion. 3.00 

11. For pendulum friction test to determine sensitiveness to frictional 

impact___ 4.00 

12. Freezing test by crusher board_ 4. 00 

13. For three experimental shots in Trauzl lead blocks_ 7. 00 

14. For three, experimental shots to determine the calories developed_ 11. 00 

15. For small-impact test to determine sensitiveness to direct impact— 6. 00 

16. For large-impact test to determine sensitiveness to direct impact_ 38. 00 

17. For maximum pressure by Bicliel pressure-gauge test- 21.00 

18. Other tests at the estimated cost. 


CONDITIONS UNDER WHICH TESTS WILL BE MADE. 

The conditions under which the Bureau of Mines will test explo¬ 
sives to determine whether they shall be placed on its lists of per¬ 
missible explosives are as follows: 

1. Tests will be made at the Explosives Experiment Station of the 
Bureau of Mines at Bruceton, Pa. 

2. Applications for tests shall be addressed to the Director, Bureau 
of Mines, Washington, D. C. 

3. The manufacturer or applicant desiring tests to be made shall 
ship, prepaid, to the Explosives Engineer, Explosives Experiment 
Station, Bureau of Mines, Bruceton, Pa., each explosive in cartridge 
sizes and quantities as requested, and send the original bill of lading 
to Explosives Engineer, Bureau of Mines, 4800 Forbes Street, Pitts¬ 
burgh, Pa. For complete official tests for permissibility, it is re¬ 
quested that the manufacturer ship each explosive in sizes and quan¬ 
tities as follows: 

Seventy-five pounds in 11-inch diameter cartridges. 

Twenty-five pounds in the smallest diameter of cartridge that he 
intends to market and, in addition, 10 cartridges of all other diam¬ 
eters in which he intends to market the explosive for use in coal 
mines. If the smallest diameter of cartridge to be shipped is 11 
inches, then 100 pounds of the explosive in this diameter is requested. 

Should the manufacturer later desire to market other diameters, 
the bureau will without charge establish the basic data for grams of 
wrapper and apparent specific gravity for those diameteis. 

Physical tests will start not less than 60 days after shipment of 
the explosive as evidenced by the bill of lading. The applicant will 
be notified of the date of starting tests in ample time to have a rep¬ 
resentative present to witness tests. 

4. No one is to be present at or participate in these tests except 
the necessary Government officers at the experiment station, their 










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assistants, and the representatives of the manufacturer of the ex¬ 
plosives or the applicant desiring tests to be made. The last shall 
be present in the capacity of observers only. 

5. The conduct of the tests shall be entirely in the hands of the 
bureau's representatives in charge of the investigation. 

6. The tests will be made in the order of the receipt of the applica¬ 
tions for them, provided the necessary quantity of explosive has 
been received at the experiment station by the date set, of which due 
notice will be given by the Bureau of Mines. 

7. On any application, not more than five explosives will be tested 
to determine their permissibility for use in coal mines, nor will more 
than five explosives be tested for any manufacturer during a fiscal 
year so long as there are other manufacturers desiring tests who 
have not had five explosives tested during that fiscal year. 

8. A list of the explosives that pass requirements satisfactorily 
will be furnished to the State mine inspectors in the several States 
and will be made public in such manner as may be considered de¬ 
sirable. 

9. The details of results of tests are to be considered confidential 
and are not to be made public prior to official publication by the 
Bureau of Mines. 

10. From time to time field samples of permissible explosives 
will be collected, and tests will be made of these explosives as they 
are supplied for use in coal mines in the various States. Field 
samples collected from original shipping cases will be tested for 
their permissibility and will be analyzed; the chemical analysis and 
the physical tests of the explosive must agree, within the tolerances 
as promulgated by the Bureau of Mines, with the chemical analysis 
and physical tests of the original sample submitted for tests. 

11. The chemical analysis of the explosive and the analysis of the 
gaseous products will be furnished only to the manufacturer. 

REMITTANCES, 

Applicants who submit an explosive for a complete official test 
to determine its permissibility for use in coal mines will be required 
to send to the Director, Bureau of Mines, Washington, D. C., check 
or bank draft, made payable to the Secretary of the Interior, cover¬ 
ing the total fee required for the complete tests. Such fees must be 
received at least three weeks prior to the date set for beginning the 
tests. Checks for the full amount charged for experimental shots, 
such as flame tests and rate of detonation tests, are required three 
weeks prior to the date set for such tests. 

TOLERANCE FOR PERMISSIBLE EXPLOSIVES. 

The tolerances promulgated by the Bureau of Mines provide for 
reasonable limits of variation in the results of analyses and tests 


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of field samples and manufacturers' samples of permissible explo¬ 
sives. These tolerances as now existing and as stated below are 
quoted, except as amended November 15, 1920, and February 26, 
1921, from Bulletin 96, 1 in which they were first published after hav¬ 
ing been established and made effective July 1, 1915. 

In order to define more exactly what is meant by the phrase simi¬ 
lar in all respects in the definition of a permissible explosive, 
namely, “A permissible explosive is an explosive which is similar 
in all respects to the sample which has passed certain tests prescribed 
by the Bureau of Mines to determine its safety for use in gaseous 
and dusty coal mines, and when used in accordance with the condi¬ 
tions prescribed by the bureau,’' the following tolerances are recom¬ 
mended for field samples or manufacturers’ samples of explosives, 
beyond which such lot of explosives can not vary and still be con¬ 
sidered permissible for use in coal mines: 



0 5 10 15 20 25 30 35 40 45 50 55 60 65 

QUANTITY OF CONSTITUENTS, PER CENT. * 

Figure 1.—Curve of limit variation in composition of permissible explosives. 


CHEMICAL ANALYSIS. 

Moisture .—To be fixed by a sliding scale from 1-J per cent at zero 
to 4 per cent at 10 per cent of moisture in original sample, this tol¬ 
erance being on total percentage of moisture in the explosive. 

Other ingredients or their equivalents. —In quantities not exceed¬ 
ing 60 per cent, according to curve shown in figure 1, except that the 
chemical tolerance for carbonaceous combustible material is-changed 
to plus or minus 3 per cent regardless of the amount of carbonaceous 
combustible material reported as present. For ingredients in quanti¬ 
ties of 60 per cent or more, the tolerance shall be plus or minus 3 
per cent: Provided , That the ingredients of a permissible explosive 
shall be considered to be those substances reported as found by the 

1 Storm, C. G., The analyses of permissible explosives: Bull. 96, Bureau of Mines, 1916, 
88 pp. 



















































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I 

Bureau of Mines in the original sample of that explosive submitted 
for test as to its permissibility : And provided further , That an equiv¬ 
alent shall be considered to be a substance which would not ma¬ 
terially alter the properties of the explosive and which would pro¬ 
duce the same result as the original substance. 

For the purpose of applying the chemical tolerance for explosives 
containing ammonium nitrate, the commercial ammonium nitrate 
will be reported as the sum of the ammonium nitrate, ammonium 
chloride, and ammonium sulphate reported as present, and the tol¬ 
erance applied to this figure. The sum of the ammonium chloride 
and the ammonium sulphate will be reported separately in a note 
and the tolerance applied to their sum will be 4 per cent of the 
commercial ammonium nitrate reported as present in the basic sam¬ 
ple, except in those cases where the tolerance thus applied would 
be less than for a separate ingredient, when the tolerances for “ other 
ingredients’’ would apply. 

PRODUCTS OF COMBUSTION DETERMINED BY BICHEL-GAUGE TESTS. 

The volume of poisonous gases from 680 grams of the explosive, 
including its wrapper, must be less than 158 liters, except that in 
case the first test yields 158 liters or more poisonous gases per 680 
grams of the explosive, including its wrapper, the average result of 
three tests agreeing within 5 per cent of each other shall be taken, 
and no explosive shall remain permissible when this average for 
poisonous gases exceeds the above standard limits. 

PHYSICAL TESTS. 2 

In making determinations of rate of detonation and unit deflective 
charge by the ballistic pendulum, the tests stop after obtaining three 
results within 5 per cent, or a total of six results. All the results 
within 10 per cent will be averaged. If there are two or more groups 
in which the results are within 10 per cent of each other, then all the 
results which are within any group will be averaged. 

APPLICATION OF TOLERANCES. 

The tolerances applied, using the ab*ove rules, are: 

Kate of detonation (the average of three to six trials within 10 per 
cent with Mettegang recorder) : Plus or minus 15 per cent. 

Unit deflective charge determined by the ballistic pendulum as 
compared with the Pittsburgh testing station standard 40 per cent 
straight nitroglycerin dynamite (the average of three to six trials 
within 10 per cent with the ballistic pendulum) : Plus or minus 10 
per cent. 

2 For the method of making the tests, see Howell, S. P., and Tiffany, J. E., Methods 
for routine work in the explosives physical laboratory of the Bureau of Mines : Tech. 
Paper, 186, Bureau of Mines, 1918, 63 pp. 



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Grams of wrapper per 100 grams of explosive: Plus or minus 2 
grams (average of four determinations) : Provided , That the manu¬ 
facturers shall submit samples of all different sizes of cartridges, to 
be considered as part of the original sample, the amount of wrapper 
to be determined for each size of sample: And 'provided further , That 
the tolerances as suggested shall be determined in comparison with 
the various diameters of samples as submitted with the original 
sample. 

Apparent specific gravity of cartridge, by sand: Plus or minus 7.5 
per cent (average of four determinations') : Provided , That actual 
density shall be determined on cartridges of the same diameter as the 
standard: And provided further , That manufacturers shall be re¬ 
quired to submit samples of all sizes. 

Gas and dust gallery No. 1: No ignition must be obtained in each 
of one or more trials. A Ate. —In the retesting of permissible explo¬ 
sives by tests 1 and 4, the charges of the explosives fired will be re¬ 
duced 10 per cent in weight from the weights originally used in order 
to eliminate any likelihood of a failure being due to the natural 
variations in the gallery conditions. 

PENDULUM FRICTION TEST. 

Each explosive must pass a test of 10 trials under the same condi¬ 
tions as originally tested, except the height of fall of the wood-fiber 
shoe will be reduced by 10 per cent in order to eliminate any likeli¬ 
hood of a failure being due to the natural variations in test con¬ 
ditions. 

FIELD SAMPLES OF PERMISSIBLE EXPLOSIVES. 

The bureau will from time to time reexamine permissible explo¬ 
sives found in commercial shipments and in the field in order to de¬ 
termine how closely they conform to the samples upon which the 
permissibility tests were originally made, and the manufacturer will 
be notified of the results of tests of all field samples. In order that 
this examination can be properly made, the tolerances as given above 
are applied in the manner stated below, according to the rules and 
regulations promulgated November 15,1920, and February 26, 1921. 
These methods of applying the tolerances supersede all previous 
methods. 

In the event that a field sample of a permissible explosive exceeds 
the tolerance for one or more items, the bureau will take the fol¬ 
lowing action: 

1. If the explosive exceeds the tolerance for any items of the 
chemical analysis, for grams of wrapper per 100 grams of explosive, 
for apparent specific gravity, for rate of detonation, or for unit 
deflective charge, the manufacturer only will be advised of the 




12 

results, except that, should these results, in the opinion of the ex¬ 
plosives engineer, indicate that the explosive is unsafe for use, 
then the operator or owner will be immediately warned, and further 
tests promptly inaugurated. 

2. If the explosive exceeds the tolerance for gallery tests, pen¬ 
dulum-friction test, or poisonous gases, the bureau will declare that 
particular lot of explosive not permissible, and a copy of the noti¬ 
fication to the consumer or owner will be furnished the manu¬ 
facturer, the notification to state that the explosive did not meet 
the requirement for gallery tests, pendulum-friction test, or poi¬ 
sonous gases, as the case may be. 

The term “ Lot of permissible explosives ” as used in the tolerances 
promulgated by the director, is defined as “ all of that explosive in 
the magazine from which the sample is procured, bearing identical 
case markings.” 

When a given lot of explosive is declared not permissible and the 
owner and the manufacturer are notified, the Bureau does not at¬ 
tempt to fix responsibilities between owner and manufacturer. 

The usual causes of an explosive exceeding the tolerances for 
chemical analysis or physical tests are two: 

1. It may not have been properly manufactured. 

2. It may not have been properly stored. 

The manufacturer is responsible for (1) because the consumer has 
no control over the method of manufacture of the explosive, but the 
consumer or owner is responsible for (2) because the manufacturer 
has no control over the conditions of storage when the explosive has 
once passed from his ownership. 

The manufacturer should exercise due care that the quality of 
the raw materials, as well as the weighing and incorporating of 
them, is similar in all respects to that for the original sample of 
explosives submitted for tests; and that the explosive is fresh and 
in first-class condition when sold. The user should store explosives 
in well-ventilated magazines, at temperatures not exceeding 90° F. 
The boxes should be placed so that the cartridges lie horizontally, 
though the tops of the boxes may be up or down. The explosives 
purchased first should be used first, and hence older explosives should 
not be stored under or behind a fresh consignment. It is well to 
purchase explosives in such quantities that they can be used 
promptly. 

H. Foster Bain, 

j 

Director. 

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Approved April 8, 1921. 
Albert B. Fall, 

Secretary, 


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